I am in china now, and I am coming for gym training, I had m visa but that is nearly finished

Dear, if you want to renew it in Thailand, you need to provide the valid entry permit or residence permit in Thailand. It may be troublesome.
Considering your situation, I think you can apply for an extension of your M type at the exit and entry administration of the local PSB in PRC directly. You need to provide your passport, valid registration form of temporary residence, the filled-out application form with your recent color photo, an invitation letter from a unit in PRC, as well as legal registration certificate of the inviter.